當URLConnection超時發生時，需要嘗試再次連接兩次，然後再更改url並再次嘗試

Question

我需要嘗試連接到字符串request_url中的url。如果連接超時發生，我需要再次重試2次，然後再調用另一個url（ans.getUrl(2)）並重復相同的邏輯。這是我的代碼片段。任何人都可以幫我解決我需要在這裏使用的邏輯嗎？

 //ans.getUrl returns a url based on the int parameter you send. It can only be 1 and 2. 
     String request_url= ans.getUrl(1); 
     try { 
        URL url; 
        URLConnection urlConn; 
        DataInputStream input; 

        //URL Creation: 
        url = new URL(request_url); 


        // URL connection channel. 
        urlConn = url.openConnection(); 

        urlConn.setConnectTimeout(2000); 

        urlConn.setDoInput(true); 

        urlConn.setDoOutput(true); 

        urlConn.setUseCaches(false); 



        // Get response data. 


        input = new DataInputStream(urlConn.getInputStream()); 

        String str; 
        System.out.println("Response XML::: "); 

        while (null != ((str = input.readLine()))) { 
         System.out.println("XML:: "+str); 
         //Write to temp file for parsing 
         FileWriter fstream = new FileWriter("response.xml", true); 
         BufferedWriter out = new BufferedWriter(fstream); 
         out.write(str+"\n"); 
         //Close the output stream 
         out.close(); 

        } 
        //Close input 
        input.close(); 


       } catch (FileNotFoundException e) { 
        System.err.println("FileNotFoundException: " 
          + e.getMessage()); 
       } catch (IOException e) { 
        System.err.println("Caught IOException: " 
          + e.getMessage()); 
       } 

Answer 1

我想包你在一個函數發送整個代碼位，然後應用圍繞該功能的重試循環。你需要允許連接異常傳播出去做這件事。